Join returns more columns then it should

[MaklaCof]

When using join query returns more columns then it should.

Steps to reproduce

This query:

            var temp = await this.Set<DbInvoiceState>().Join(
                    this.Set<DbInvoiceState>().GroupBy(t => t.InvoiceId).Select(t => new { t.Key, MaxInserted = t.Max(t2 => t2.InsertedDateTime) }),
                    t => new
                    {
                        t.InvoiceId,
                        t.InsertedDateTime,
                        states = states.Contains(t.DocumentState)
                    },
                    t => new
                    {
                        InvoiceId = t.Key,
                        InsertedDateTime = t.MaxInserted,
                        states = true
                    },
                    (t, t2) => t2.Key)
                .ToListAsync();

executes this query:

SELECT [t1].[Key], [t1].[MaxInserted]   //<--------- why this column?
FROM [Postman].[Invoice-States] AS [t]
INNER JOIN (
    SELECT [t0].[InvoiceId] AS [Key], MAX([t0].[InsertedDateTime]) AS [MaxInserted]
    FROM [Postman].[Invoice-States] AS [t0]
    GROUP BY [t0].[InvoiceId]
) AS [t1] ON (([t].[InvoiceId] = [t1].[Key]) AND ([t].[InsertedDateTime] = [t1].[MaxInserted])) AND [t].[DocumentState] IN (CAST(11 AS tinyint), CAST(12 AS tinyint), CAST(13 AS tinyint))

but it should be without [t1].[MaxInserted:

SELECT [t1].[Key]
FROM [Postman].[Invoice-States] AS [t]
INNER JOIN (
    SELECT [t0].[InvoiceId] AS [Key], MAX([t0].[InsertedDateTime]) AS [MaxInserted]
    FROM [Postman].[Invoice-States] AS [t0]
    GROUP BY [t0].[InvoiceId]
) AS [t1] ON (([t].[InvoiceId] = [t1].[Key]) AND ([t].[InsertedDateTime] = [t1].[MaxInserted])) AND [t].[DocumentState] IN (CAST(11 AS tinyint), CAST(12 AS tinyint), CAST(13 AS tinyint))

Further technical details

EF Core version: 2.1.2
Database Provider: Microsoft.EntityFrameworkCore.SqlServer
Operating system: Win-10-64bit
IDE: (Visual Studio 2017 15.8.3)

Also tried

this query

            var temp = await this.Set<DbInvoiceState>().Join(
                    this.Set<DbInvoiceState>().GroupBy(t => t.InvoiceId).Select(t => new { t.Key, MaxInserted = t.Max(t2 => t2.InsertedDateTime) }),
                    t => new
                    {
                        t.InvoiceId,
                        t.InsertedDateTime,
                        states = states.Contains(t.DocumentState)
                    },
                    t => new
                    {
                        InvoiceId = t.Key,
                        InsertedDateTime = t.MaxInserted,
                        states = true
                    },
                    (t, t2) => t.InvoiceId)       //   <--------   changed
                .ToListAsync();

but nothing is chaged: SELECT [t1].[Key], [t1].[MaxInserted], [t].[InvoiceId]